/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This program scans all the source files for code to handle various
 * special events and combines this code into one file.  This (allegedly)
 * improves the structure of the program since there is no need for
 * anyone outside of a module to know that that module performs special
 * operations on particular events.
 *
 * Usage:  mkinit sourcefile...
 */


#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>


/*
 * OUTFILE is the name of the output file.  Output is initially written
 * to the file OUTTEMP, which is then moved to OUTFILE.
 */

#define OUTFILE "init.c"
#define OUTTEMP "init.c.new"


/*
 * A text structure is basicly just a string that grows as more characters
 * are added onto the end of it.  It is implemented as a linked list of
 * blocks of characters.  The routines addstr and addchar append a string
 * or a single character, respectively, to a text structure.  Writetext
 * writes the contents of a text structure to a file.
 */

#define BLOCKSIZE 512

struct text {
	char *nextc;
	int nleft;
	struct block *start;
	struct block *last;
};

struct block {
	struct block *next;
	char text[BLOCKSIZE];
};


/*
 * There is one event structure for each event that mkinit handles.
 */

struct event {
	char *name;		/* name of event (e.g. INIT) */
	char *routine;		/* name of routine called on event */
	char *comment;		/* comment describing routine */
	struct text code;	/* code for handling event */
};


char writer[] = "\
/*\n\
 * This file was generated by the mkinit program.\n\
 */\n\
\n";

char init[] = "\
/*\n\
 * Initialization code.\n\
 */\n";

char exitreset[] = "\
/*\n\
 * This routine is called when an error or an interrupt occurs in an\n\
 * interactive shell and control is returned to the main command loop\n\
 * but prior to exitshell. \n\
 */\n";

char forkreset[] = "\
/*\n\
 * This routine is called when we enter a subshell.\n\
 */\n";

char reset[] = "\
/*\n\
 * This routine is called when an error or an interrupt occurs in an\n\
 * interactive shell and control is returned to the main command loop.\n\
 */\n";


struct event event[] = {
	{"INIT", "init", init},
	{"EXITRESET", "exitreset", exitreset},
	{"FORKRESET", "forkreset", forkreset},
	{"RESET", "reset", reset},
	{NULL, NULL}
};


char *curfile;				/* current file */
int linno;				/* current line */
char *header_files[200];		/* list of header files */
struct text defines;			/* #define statements */
struct text decls;			/* declarations */
int amiddecls;				/* for formatting */


void readfile(char *);
int match(char *, char *);
int gooddefine(char *);
void doevent(struct event *, FILE *, char *);
void doinclude(char *);
void dodecl(char *, FILE *);
void output(void);
void addstr(char *, struct text *);
void addchar(int, struct text *);
void writetext(struct text *, FILE *);
FILE *ckfopen(char *, char *);
void *ckmalloc(int);
char *savestr(char *);
static void error(char *);
int main(int, char **);

#define equal(s1, s2)	(strcmp(s1, s2) == 0)

int
main(int argc, char **argv)
{
	char **ap;

	header_files[0] = "\"shell.h\"";
	header_files[1] = "\"mystring.h\"";
	header_files[2] = "\"init.h\"";
	for (ap = argv + 1 ; *ap ; ap++)
		readfile(*ap);
	output();
	rename(OUTTEMP, OUTFILE);
	exit(0);
	/* NOTREACHED */
}


/*
 * Parse an input file.
 */

void
readfile(char *fname)
{
	FILE *fp;
	char line[1024];
	struct event *ep;

	fp = ckfopen(fname, "r");
	curfile = fname;
	linno = 0;
	amiddecls = 0;
	while (fgets(line, sizeof line, fp) != NULL) {
		linno++;
		for (ep = event ; ep->name ; ep++) {
			if (line[0] == ep->name[0] && match(ep->name, line)) {
				doevent(ep, fp, fname);
				break;
			}
		}
		if (line[0] == 'I' && match("INCLUDE", line))
			doinclude(line);
		if (line[0] == 'M' && match("MKINIT", line))
			dodecl(line, fp);
		if (line[0] == '#' && gooddefine(line)) {
		        char *cp;
			char line2[1024];
			static const char undef[] = "#undef ";

			strcpy(line2, line);
			memcpy(line2, undef, sizeof(undef) - 1);
			cp = line2 + sizeof(undef) - 1;
			while(*cp && (*cp == ' ' || *cp == '\t'))
			        cp++;
			while(*cp && *cp != ' ' && *cp != '\t' && *cp != '\n')
			        cp++;
			*cp++ = '\n'; *cp = '\0';
			addstr(line2, &defines);
			addstr(line, &defines);
		}
	}
	fclose(fp);
}


int
match(char *name, char *line)
{
	char *p, *q;

	p = name, q = line;
	while (*p) {
		if (*p++ != *q++)
			return 0;
	}
	if (*q != '{' && *q != ' ' && *q != '\t' && *q != '\n')
		return 0;
	return 1;
}


int
gooddefine(char *line)
{
	char *p;

	if (! match("#define", line))
		return 0;			/* not a define */
	p = line + 7;
	while (*p == ' ' || *p == '\t')
		p++;
	while (*p != ' ' && *p != '\t') {
		if (*p == '(')
			return 0;		/* macro definition */
		p++;
	}
	while (*p != '\n' && *p != '\0')
		p++;
	if (p[-1] == '\\')
		return 0;			/* multi-line definition */
	return 1;
}


void
doevent(struct event *ep, FILE *fp, char *fname)
{
	char line[1024];
	int indent;
	char *p;

	sprintf(line, "\n      /* from %s: */\n", fname);
	addstr(line, &ep->code);
	addstr("      {\n", &ep->code);
	for (;;) {
		linno++;
		if (fgets(line, sizeof line, fp) == NULL)
			error("Unexpected EOF");
		if (equal(line, "}\n"))
			break;
		indent = 6;
		for (p = line ; *p == '\t' ; p++)
			indent += 8;
		for ( ; *p == ' ' ; p++)
			indent++;
		if (*p == '\n' || *p == '#')
			indent = 0;
		while (indent >= 8) {
			addchar('\t', &ep->code);
			indent -= 8;
		}
		while (indent > 0) {
			addchar(' ', &ep->code);
			indent--;
		}
		addstr(p, &ep->code);
	}
	addstr("      }\n", &ep->code);
}


void
doinclude(char *line)
{
	char *p;
	char *name;
	char **pp;

	for (p = line ; *p != '"' && *p != '<' && *p != '\0' ; p++);
	if (*p == '\0')
		error("Expecting '\"' or '<'");
	name = p;
	while (*p != ' ' && *p != '\t' && *p != '\n')
		p++;
	if (p[-1] != '"' && p[-1] != '>')
		error("Missing terminator");
	*p = '\0';

	/* name now contains the name of the include file */
	for (pp = header_files ; *pp && ! equal(*pp, name) ; pp++);
	if (*pp == NULL)
		*pp = savestr(name);
}


void
dodecl(char *line1, FILE *fp)
{
	char line[1024];
	char *p, *q;

	if (strcmp(line1, "MKINIT\n") == 0) { /* start of struct/union decl */
		addchar('\n', &decls);
		do {
			linno++;
			if (fgets(line, sizeof line, fp) == NULL)
				error("Unterminated structure declaration");
			addstr(line, &decls);
		} while (line[0] != '}');
		amiddecls = 0;
	} else {
		if (! amiddecls)
			addchar('\n', &decls);
		q = NULL;
		for (p = line1 + 6 ; *p && strchr("=/\n", *p) == NULL; p++)
			continue;
		if (*p == '=') {		/* eliminate initialization */
			for (q = p ; *q && *q != ';' ; q++);
			if (*q == '\0')
				q = NULL;
			else {
				while (p[-1] == ' ')
					p--;
				*p = '\0';
			}
		}
		addstr("extern", &decls);
		addstr(line1 + 6, &decls);
		if (q != NULL)
			addstr(q, &decls);
		amiddecls = 1;
	}
}



/*
 * Write the output to the file OUTTEMP.
 */

void
output(void)
{
	FILE *fp;
	char **pp;
	struct event *ep;

	fp = ckfopen(OUTTEMP, "w");
	fputs(writer, fp);
	for (pp = header_files ; *pp ; pp++)
		fprintf(fp, "#include %s\n", *pp);
	fputs("\n\n\n", fp);
	writetext(&defines, fp);
	fputs("\n\n", fp);
	writetext(&decls, fp);
	for (ep = event ; ep->name ; ep++) {
		fputs("\n\n\n", fp);
		fputs(ep->comment, fp);
		fprintf(fp, "\nvoid\n%s() {\n", ep->routine);
		writetext(&ep->code, fp);
		fprintf(fp, "}\n");
	}
	fclose(fp);
}


/*
 * A text structure is simply a block of text that is kept in memory.
 * Addstr appends a string to the text struct, and addchar appends a single
 * character.
 */

void
addstr(char *s, struct text *text)
{
	while (*s) {
		if (--text->nleft < 0)
			addchar(*s++, text);
		else
			*text->nextc++ = *s++;
	}
}


void
addchar(int c, struct text *text)
{
	struct block *bp;

	if (--text->nleft < 0) {
		bp = ckmalloc(sizeof *bp);
		if (text->start == NULL)
			text->start = bp;
		else
			text->last->next = bp;
		text->last = bp;
		text->nextc = bp->text;
		text->nleft = BLOCKSIZE - 1;
	}
	*text->nextc++ = c;
}

/*
 * Write the contents of a text structure to a file.
 */
void
writetext(struct text *text, FILE *fp)
{
	struct block *bp;

	if (text->start != NULL) {
		for (bp = text->start ; bp != text->last ; bp = bp->next) {
			if ((fwrite(bp->text, sizeof (char), BLOCKSIZE, fp)) != BLOCKSIZE)
				error("Can't write data\n");
		}
		if ((fwrite(bp->text, sizeof (char), BLOCKSIZE - text->nleft, fp)) != (BLOCKSIZE - text->nleft))
			error("Can't write data\n");
	}
}

FILE *
ckfopen(char *file, char *mode)
{
	FILE *fp;

	if ((fp = fopen(file, mode)) == NULL) {
		fprintf(stderr, "Can't open %s\n", file);
		exit(2);
	}
	return fp;
}

void *
ckmalloc(int nbytes)
{
	char *p;

	if ((p = malloc(nbytes)) == NULL)
		error("Out of space");
	return p;
}

char *
savestr(char *s)
{
	char *p;

	p = ckmalloc(strlen(s) + 1);
	strcpy(p, s);
	return p;
}

static void
error(char *msg)
{
	if (curfile != NULL)
		fprintf(stderr, "%s:%d: ", curfile, linno);
	fprintf(stderr, "%s\n", msg);
	exit(2);
	/* NOTREACHED */
}
